Abstract:We study a precise and computationally tractable notion of operator complexity in holographic quantum theories, including the ensemble dual of Jackiw-Teitelboim gravity and two-dimensional holographic conformal field theories. This is a refined, “microcanonical” version of K-complexity that applies to theories with infinite or continuous spectra (including quantum field theories), and in the holographic theories we study exhibits exponential growth for a scrambling time, followed by linear growth until saturat… Show more
“…We will leave a more thorough analysis in two-dimensional CFT for future work. It is also worth emphasizing other proposals for the definition of operator complexity [25,26,27,28,29,30] and it would be interesting to compare them in our context. One can potentially use these to diagnose more fine-grained properties of the collision in the interior.…”
Section: Discussionmentioning
confidence: 99%
“…of operators [18,19,20,21,22,23,24] and their operator complexity [25,26,27,28,29,30]. Some other related recent studies of the black hole interior using ideas of operator reconstruction include [31,32,33,34,35,36,37] and [38,39,40].…”
We study collisions between localized shockwaves inside a black hole interior. We give a holographic boundary description of this process in terms of the overlap of two growing perturbations in a shared quantum circuit. The perturbations grow both exponentially as well as ballistically. Due to a competition between different physical effects, the circuit analysis shows dependence on the transverse locations and exhibits four regimes of qualitatively different behaviors. On the gravity side we study properties of the post-collision geometry, using exact calculations in simple setups and estimations in more general circumstances. We show that the circuit analysis offers intuitive and surprisingly accurate predictions about gravity computations involving non-linear features of general relativity.
“…We will leave a more thorough analysis in two-dimensional CFT for future work. It is also worth emphasizing other proposals for the definition of operator complexity [25,26,27,28,29,30] and it would be interesting to compare them in our context. One can potentially use these to diagnose more fine-grained properties of the collision in the interior.…”
Section: Discussionmentioning
confidence: 99%
“…of operators [18,19,20,21,22,23,24] and their operator complexity [25,26,27,28,29,30]. Some other related recent studies of the black hole interior using ideas of operator reconstruction include [31,32,33,34,35,36,37] and [38,39,40].…”
We study collisions between localized shockwaves inside a black hole interior. We give a holographic boundary description of this process in terms of the overlap of two growing perturbations in a shared quantum circuit. The perturbations grow both exponentially as well as ballistically. Due to a competition between different physical effects, the circuit analysis shows dependence on the transverse locations and exhibits four regimes of qualitatively different behaviors. On the gravity side we study properties of the post-collision geometry, using exact calculations in simple setups and estimations in more general circumstances. We show that the circuit analysis offers intuitive and surprisingly accurate predictions about gravity computations involving non-linear features of general relativity.
“…If the descent of the Lanczos sequence had a slightly convex profile, the region where the strength of the fluctuations becomes comparable to the mean value on top of which they are added would be pushed towards the right. In fact, the analytical expression for the Lanczos sequence in RMT at large size has this feature [19]: the quasi-linear descent gets eventually modified by a square-root behavior. With this motivation, we use the following Ansatz for the toy Lanczos sequence:…”
Section: Disordered Sequence With Ascent and Quasi-linear Convex Descentmentioning
confidence: 99%
“…It also does not depend on a tolerance parameter as gate complexity does [1], or on a penalty metric as geometric complexity does [11]. Other recent work related to the study of K-complexity includes [17][18][19][20][21][22][23]. In particular, works like [17,19,22,24] have applied it to the realm of holographic conformal field theory.…”
Section: Introductionmentioning
confidence: 99%
“…Other recent work related to the study of K-complexity includes [17][18][19][20][21][22][23]. In particular, works like [17,19,22,24] have applied it to the realm of holographic conformal field theory.…”
A notion of quantum complexity can be effectively captured by quantifying the spread of an operator in Krylov space as a consequence of time evolution. Complexity is expected to behave differently in chaotic many-body systems, as compared to integrable ones. In this paper we investigate Krylov complexity for the case of interacting integrable models at finite size and find that complexity saturation is suppressed as compared to chaotic systems. We associate this behavior with a novel localization phenomenon on the Krylov chain by mapping the theory of complexity growth and spread to an Anderson localization hopping model with off-diagonal disorder, and find that increasing the amount of disorder effectively suppresses Krylov complexity. We demonstrate this behavior for an interacting integrable model, the XXZ spin chain, and show that the same behavior results from a phenomenological model that we define. This model captures the essential features of our analysis and is able to reproduce the behaviors we observe for chaotic and integrable systems via an adjustable disorder parameter.
A number of recent works have argued that quantum complexity, a well-known concept in computer science that has re-emerged recently in the context of the physics of black holes, may be used as an efficient probe of novel phenomena such as quantum chaos and even quantum phase transitions. In this article, we provide further support for the latter, using a 1-dimensional p-wave superconductor — the Kitaev chain — as a prototype of a system displaying a topological phase transition. The Hamiltonian of the Kitaev chain manifests two gapped phases of matter with fermion parity symmetry; a trivial strongly-coupled phase and a topologically non-trivial, weakly-coupled phase with Majorana zero-modes. We show that Krylov-complexity (or, more precisely, the associated spread-complexity) is able to distinguish between the two and provides a diagnostic of the quantum critical point that separates them. We also comment on some possible ambiguity in the existing literature on the sensitivity of different measures of complexity to topological phase transitions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.